Soy-based phosphatidylserine may normalise the stress reactions of the nervous system and hormone glands in highly stressed males, according to research.

The researchers from Germany, Switzerland and Israel looked at the impact of daily oral supplementation of phosphatidylserine (PS) and phosphatidic acid complex (PA) for a 42-day period on the hypothalamus-pituitary-adrenal axis (HPAA).

The HPAA refers to the complex feedback relationship between the endocrine glands which secrete hormones into the blood, the hypothalamus which is a part of the brain that connects the nervous system to the endocrine system, the pituitary gland which sits below the hypothalamus and secretes hormones and the adrenal glands which sit at the top of the kidneys and secretes stress hormones.

Prolonged stress induces a hyper-activation of the HPAA, which can then lead to a state of "hypo-activation". The research suggested that daily supplementation with 400 mg of phosphatidylserine (PS) and 400 mg of phosphatidic acid complex (PA) may normalise this hyper response.

A stressful process

The research, published in the journal Lipids in Health and Disease, looked at 75 healthy male volunteers stratified by chronic stress level and given either a placebo or 200 mg PS and 200 mg PA or 400 mg PS and 400 mg PA per day.

They concluded: “Compared to placebo, a supplementation with a daily dose of PAS 400 was effective in normalising the ACTH [adrenocorticotropic hormone], salivary and serum cortisol responses to the TSST [Trier Social Stress Test] in chronically high but not in low stressed subjects.”

Meanwhile supplementation in the 200 mg group did not result in any significant differences, compared to the placebo. They also found no difference to heart rate, pulse transit time or psychological stress response.

The researchers said: “As in our previous PAS study, effects of PAS 400 could only be observed for endocrine but not for autonomic stress responses. If PAS would primarily affect the stress response network in the brain, one would expect common secondary effects on psychological, endocrine, and autonomic measures.

“This is unlikely, since in both studies psychological effects were inconsistent and autonomic effects could not be observed. This points to the possibility that PAS primarily targets peripheral components of the HPAA.”

Regulating stress, regulating phosphatidylserine

Phosphatidylserine won EU novel foods approval
for yoghurt foods, bars, chocolate and milk powder drinks last month following an application from Lonza, having already secured approval for use in supplements.

In 2010 however a health claim application for phosphatidyl serine for the effects “memory and cognitive functioning in the elderly”, “mental health/cognitive function” and “stress reduction and enhanced memory function” was rejected by the European Food Safety Authority (EFSA), saying a cause and effect relationship could not be established.

In its decision
, the authority said the information provided did not allow it to characterise the food constituent, concluding therefore that phosphatidyl serine was "not sufficiently characterised".

Meanwhile, America’s Food and Drug Administration (FDA) responded to an qualified health claim application in 2003, saying: “Our conclusion
is that there is not significant scientific agreement that phosphatidylserine may reduce the risk of dementia or cognitive dysfunction in the elderly.”

They instead proposed the addition of a disclaimer to the claim to avoid misleading consumers, stating in each case it may have an effect but the scientific evidence was weak.